Patent GB-468726-A (GB)
Title: Improvements in or relating to manually operated vacuum chests for closuring containers in vacuum
IPC: A23L3/10
Filed: 1936-05-29
Abstract: 468,726. Closuring containers in vacuum. BARLOW, R., and PATERSON, C. C. May 29, 1936, No. 15272. [Class 125 (ii)] A chest for closuring containers in vacuum comprises a manually operated pressure plate for pressing lids on to containers, a resilient member subjected to the pressure exerted on the containers and constructed to resist pressure up to a predetermined amount and means actuated on the deformation of the resilient member when that amount is exceeded to give an indication or warning to the operator that excessive pressure is being used. The chest 1 is mounted on a filler 2 on a base 3, and has a hinged door 4 to provide an hermetic seal. A pressure plate 5 is secured to a spindle 6 passing through a packing gland 17 in the top of the chest and support 7 secured to the top of the chest. The spindle 6 is threaded at 8 and passes through a sleeve 10 threaded at its upper end 12 and keyed to the hand wheel 9. The sleeve 10 is normally held from axial movement by a compression spring 13, bearing at its lower end against an adjustable collar 14 screwed to the bottom of the sleeve, and with its upper end against a collar 15 bearing on the lower race of a thrust bearing 16. Pivoted to support 17 is a pointer 18 having a crosspiece 19 one arm of which supports a roller 20 against the hand wheel 9, while the other is connected by a coil spring 21 to the member 7. Rotation of wheel 9 moves plate 5 into contact with lids of boxes in the chest. The chest is then evacuated and further pressure applied. At a predetermined pressure the spring 13 yields permitting sleeve 10 and wheel 9 to move upwardly so that pointer 18 turns to warn the operator. In place of a pointer, electrical contacts may be provided so that audible or visible warning is given of excess pressure, or a relay is operated and air is admitted to the chest giving a shrill note as it enters. Completion of the circuit may also stop the vacuum pump. Thus the plate may be provided with a laminated spring, the free ends of the larger lever of which are guided on the upper face of the plate by a link connection. Pressure on the plate flattens the spring, giving a cushioning effect. One terminal of an electric circuit may be mounted on the plate, the other being carried on the centre part of the spring or the shackle or the end of the spindle, contact being effected by relative movement between the spindle and plate or deflection of the spring. The terminal on the plate is supported on springs so that the contact may follow the movement of the spindle and retain the circuit complete. The spring supporting the terminal is adjustable so that the amount of excess pressure necessary to produce contact may be accurately adjusted. If desired springs may be disposed between a false bottom and the bottom of the chest contacts, adjustable if desired, being disposed to meet when the false bottom is depressed. After displacement of the resilient member to warn the operator of excess pressure a positive stop may be applied to prevent deformation of the containers. The resilient member may be of rubber or may be a hydraulic device instead of a spring. Attachments may be provided for use with vacuum chests of ordinary construction according to the present invention.